Oscillators for wireless power transfer

ABSTRACT

A signal generator generates an electrical signal that is sent to an amplifier, which increases the power of the signal using power from a power source. The amplified signal is fed to a sender transducer to generate ultrasonic waves that can be focused and sent to a receiver. The receiver transducer converts the ultrasonic waves back into electrical energy and stores it in an energy storage device, such as a battery, or uses the electrical energy to power a device. In this way, a device can be remotely charged or powered without having to be tethered to an electrical outlet.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. patent application Ser. No.14/635,861, filed on Mar. 2, 2015, which claims the benefit of U.S.patent application Ser. No. 13/477,551, filed on May 22, 2012, whichclaims the benefit of U.S. Provisional Patent Application No.61/490,988, filed May 27, 2011, all of which are herein incorporatedherein by reference in its entirety. This application is also related toU.S. patent application Ser. No. 13/477,452, entitled, “SenderCommunications for Wireless Power Transfer”; U.S. patent applicationSer. No. 13/477,551, entitled “Receiver Communications for WirelessPower Transfer”; U.S. patent application Ser. No. 13/477,555, entitled“Sender Transducer for Wireless Power Transfer”; U.S. patent applicationSer. No. 13/477,557, entitled, “Receiver Transducer for Wireless PowerTransfer”; U.S. patent application Ser. No. 13/477,565, entitled,“Sender Controller for Wireless Power Transfer”; and U.S. patentapplication Ser. No. 13/477,574, entitled, “Receiver Controller forWireless Power Transfer”; all of which were filed on May 22, 2012, andeach and every one of which is incorporated herein in its entirety.

BACKGROUND

Devices that require energy to operate can be plugged into a powersource using a wire. This can restrict the movement of the device andlimit its operation to within a certain maximum distance from the powersource. Even most battery-powered devices must periodically be tetheredto a power source using a cord, which can be inconvenient andrestrictive.

BRIEF SUMMARY

According to an embodiment of the disclosed subject matter, a systemcomprising at least one first transducer adapted and configured toconvert electrical energy to ultrasonic energy in the form of ultrasonicwaves. The first transducer is in communication with a first controller,and the first controller is in communication with a first communicationdevice.

In another embodiment of the disclosed subject matter, a systemcomprises at least one second transducer adapted and configured toconvert ultrasonic energy in the form of ultrasonic waves to electricalenergy. The second transducer is in communication with a secondcontroller, and the second controller is in communication with a secondcommunication device.

Additional features, advantages, and embodiments of the disclosedsubject matter may be set forth or apparent from consideration of thefollowing detailed description, drawings, and claims. Moreover, it is tobe understood that both the foregoing summary and the following detaileddescription are exemplary and are intended to provide furtherexplanation without limiting the scope of the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the disclosed subject matter, are incorporated in andconstitute a part of this specification. The drawings also illustrateembodiments of the disclosed subject matter and together with thedetailed description serve to explain the principles of embodiments ofthe disclosed subject matter. No attempt is made to show structuraldetails in more detail than may be necessary for a fundamentalunderstanding of the disclosed subject matter and various ways in whichit may be practiced.

FIG. 1 shows a system in accordance with an embodiment of the invention.

FIG. 2 shows a system in accordance with an embodiment of the invention.

FIG. 3 shows a system in accordance with an embodiment of the invention.

DETAILED DESCRIPTION

Embodiments of the disclosed subject matter can convert electricalenergy into acoustic energy, which can be beamed to a device where it isconverted back into electrical energy. The converted electrical energycan be used to power the device and to charge one or more energy storagecomponents of the device, such as a battery, a capacitor, etc. This canobviate the need for constant or periodic tethering to a power sourceusing a cord. Embodiments can transfer energy to several devices atonce, in rotation or in any suitable sequence, with dwell times of anysuitable duration.

FIG. 1 shows a system in accordance with the disclosed subject matter.Transmitter 101 can receive electrical energy from power source 102(such as an electrical outlet or a battery) as input. Signal generator103 can generate a signal that can be amplified by amplifier 104. Thiscan be done under the control of controller 105. The amplified signalcan be sent to sending transducer 106, and the ultrasonic energy in theform of ultrasound waves 107 can be transmitted through a medium such asthe air. Receiver 108 can includes receiving transducer 109, whichreceives ultrasonic energy in the form of ultrasonic waves and convertsit to electrical energy, which can be used to charge energy storagedevice 110 or power processor 111. Examples of energy storage device 110can include a battery, a capacitor, an induction circuit, etc. Examplesof device 105 can include a smartphone (such as an Android mobiledevice, an iPhone, a mobile device having a Microsoft operating system),a portable computer (such as an Apple laptop, a laptop having aMicrosoft operating system, etc.), an electronic content reader, (suchas the Amazon Kindle, the Apple iPad, etc.) and so on. Controller 111can control the receiving transducer 109 and/or energy storage device110.

Controller 105 can be coupled to antenna 112 and controller 111 can becoupled to antenna 113. As described below, the transmitter controller105 and receiver controller 111 can communicate through antennas 112 and113.

Sending transducer 106 can comprise a plurality of transducers arrangedin an array that can produce a focused beam of ultrasonic energy.Sending transducer 106 may include at least one Capacitive Micromachined Ultrasonic Transducer (CMUT), a Capacitive UltrasonicTransducer (CUT), an electrostatic transducer or any other transducersuitable for converting electrical energy into acoustic energy. Togenerate focused ultrasonic energy via a phased array, sendingtransducer 106 can include a timed delay transducer or a parametricarray transducer, or a bowl-shaped transducer array. Transmitter 101 canoperate for example between about 20 to about 120 kHz for transmissionof ultrasonic energy through air, and up to about 155 dB, for example.For ultrasonic transmission through other medium, transmitter 101 canoperate at frequencies greater than or equal to 1 MHz, for example.Sending transducer 106 may have a high electromechanical conversion, forexample an efficiency of about 40%, corresponding to about a 3 dB loss.

Transmitter controller 105 can cause the sending transducer 106 to emitultrasonic waves based on the proximity of the sending transducer 106(or transmitter 101 in general) to receiving transducer 109. Receivingtransducer 109 can convert ultrasonic energy received from sendingtransducer 106 to electrical energy. As used herein, proximity can bethe actual or effective distance between the sending transducer 106 orthe like and receiving transducer 109 or the like. Effective distancecan be based on the efficiency of energy transmission between sendingtransducer 106 and receiving transducer 109 based on various factorsthat can include, without limitation, their relative locations; thecharacteristics of the conductive medium (e.g., the air, tissue, etc.)between transmitter and receiver; the relative orientation of thetransmitter and receiver; obstructions that may exist between thetransmitter and receiver; relative movement between transmitter andreceiver; etc. In some cases, a first transmitter/receiver pair may havea higher proximity than a second transmitter/receiver pair, even thoughthe first pair is separated by a greater absolute distance than thesecond pair.

Transmitter controller 105 may cause a beam of ultrasonic energy to bedirected toward receiver transducer 109. Further, transmitter controller105 can cause sending transducer 105 to emit ultrasonic waves having atleast one frequency and at least one amplitude. Transmitter controller105 can cause the sending transducer 106 to change the frequency and/oramplitude of at least some of the ultrasonic waves based on theproximity and/or location of sending transducer 106 to receivingtransducer 109. Additionally, transmitter controller 105 can causesending transducer 105 to change the amplitude of at least some of theultrasonic waves based on the frequency of the ultrasonic energy emittedby sending transducer or based on information regarding the receipt ofultrasonic energy as determined by receiving controller 111.

Sending controller 105 and receiving controller 111 can communicatethrough antennas 112 and 113. In this way, receiving controller canessentially control the character and amplitude of the energy generatedby sending transducer 106 by sending commands to sending controller 105.Also, sending controller 105 can control the characteristics of sendingtransducer 106 based upon data and/or commands received from receivingcontroller 111. Likewise, sending controller can control thecharacteristics of the energy sent by sending transducer 106independently of input from receiving controller 111.

Transmitter controller 105 can include a transmitter communicationsdevice (not shown) that can send an interrogation signal to detectreceiving transducer 109. The transmitter communications device can senda control signal to a receiver communications device (not shown) coupledto receiver controller 111. Receiver controller 111 can control receivertransducer 109. The control signal may include the frequency and/oramplitude of the ultrasonic energy emitted by sending transducer 106.The control signal can be used to determine the proximity and/ororientation of sending transducer 106 to receiving transducer 109.Additionally, the control signal may include an instruction to beexecuted by receiving controller 109 and may also include informationabout the impedance of sending transducer 106.

The sender communication device can receive a control signal from thereceiver communication device, which can be in communication withreceiver controller 111. The control signal may include a desired powerlevel, the frequency and/or amplitude of ultrasonic energy received fromthe sender transducer 106. Additionally, the control signal may includethe impedance of the receiving transducer 109, a request for power,and/or an instruction to be executed by the transmitter controller 105.The control signal may be used to determine the proximity of the sendertransducer to the receiver transducer and/or the relative orientation ofthe sender transducer to the receiver transducer. Further, the controlsignal may also indicate a power status. Such a power status canindicate, for example, the amount of power available to the receiver108, e.g., percent remaining, percent expended, amount of joules orequivalent left in the receiver energy storage device 110. The controlsignal may be transmitted by modulating at least some of the ultrasonicwaves and/or may be transmitted out-of-band, e.g., using a separateradio frequency transmitter, or by sending a signal through a cellulartelephone network or via a Wi-Fi network. For example, the signal may betransmitted by text, instant message, email, etc.

Transmitter 101 can further include a signal generator 103, variouslyknown as a function generator, pitch generator, arbitrary waveformgenerator, or digital pattern generator, which can generate one or morewaveforms of ultrasonic waves. A controller 105 can itself include anoscillator, an amplifier, a processor, memory, etc., (not shown.) Theprocessor of the controller can also execute instructions stored inmemory to produce specific waveforms using the signal generator 103. Thewaveforms produced by the signal generator 103 can be amplified by theamplifier 104. The controller 105 can regulate how and when thetransducer 106 can be activated.

The electrical power source 102 for transmitter 101 may be an AC or DCpower source. Where an AC power source is used, transmitter 101 mayinclude a power processor 114 that is electrically connected with thesignal generator 103. The power processor 114 can receive AC power fromthe power source 102 to generate DC power.

Transmitted ultrasound beams 107 can undergo constructive interferenceand generate a narrow main lobe and low-level side lobes to help focusand/or direct the ultrasonic energy. The ultrasonic energy generated bytransmitter 101 may also be focused using techniques such as geometricfocusing, time reversal methods, beam forming via phase lags, or throughthe use of an electronically controlled array.

The transmitter 101 may scan an area for receivers, may sense locationof a receiver within a room, may track a receiver, and may steer anultrasonic beam toward the receiver. Transmitter 101 may optionally notemit ultrasonic energy unless a receiver 108 is determined to be withina given range.

Transmitter 101 may be mechanically and/or electronically orientedtowards a receiver 108. For example, in some embodiments, thetransmitter can be tilted in the XY-direction using a motor and the beamcan be steered electronically in the Z-direction. The transmitter 101may transmit ultrasonic energy to the receiver 108 via line of sighttransmission or by spreading the ultrasound pulse equally in alldirections. For line of sight transmission, the transmitter 101 andreceiver 108 may be physically oriented toward each other: thetransmitter 101 can physically or electronically (or both) be aimed atthe receiver 108 or the receiver 108 can be so aimed at the transmitter101. The transmitter 101 may transmit signals, such as an ultrasonic,radio, or other such signal, to be sensed by the receiver 108 for thepurpose of detecting orientation, location, communication, or otherpurposes, or vice versa. One or both of the transmitter 101 and receiver108 can include a signal receiver such as antennas 112 and 113,respectively, that can receive signals from the receiver 108 ortransmitter 101, respectively. Likewise, signals may be transmitted fromtransmitter 101 to receiver 108 using the ultrasonic waves themselves.

The transmitter 101 can be thermo regulated by managing the duty cyclesof the signal generator and other components. Thermoregulation can alsobe achieved by attaching heat sinks to the transmitting transducer 106,using fans, and/or running a coolant through the transmitter, and otherthermoregulation methods.

Receiver 108 can include a receiver transducer 109 that can convertultrasonic energy in the form of ultrasonic waves to electrical energy.Receiver transducer 109 may include one or more transducers arranged inan array that can receive unfocused or a focused beam of ultrasonicenergy. Receiver transducer 108 may include at least one CapacitiveMicromachined Ultrasonic Transducer (CMUT), a Capacitive UltrasonicTransducer (CUT), or an electrostatic transducer, or apiezoelectric-type transducer described below, a combination thereof orany other type or types of transducer that can convert ultrasound intoelectrical energy. For receiving focused ultrasonic energy via a phasedarray, receiver transducer 109 may include a timed delay transducer or aparametric transducer. Receiver 108 can operate for example betweenabout 20 to about 120 kHz for receipt of ultrasonic energy through air,and up to about 155 dB, for example. For receiving ultrasonic energythrough other medium, receiver 108 can operate at frequencies greaterthan or equal to 1 MHz, for example. Receiver transducer 109 can have ahigh electromechanical conversion efficiency, for example of about 40%,corresponding to about a 3 dB loss.

Receiver transducer 109 may supply electrical energy to an energystorage device 110 and/or a processor 115. Examples of an energy storagedevice 110 can include, but are not limited to, a battery, a capacitivestorage device, an electrostatic storage device, etc. Examples of aprocessor can include, but not limited to, a processor or chipset for asmartphone (such as an Android mobile device, an iPhone, a mobile devicehaving a Microsoft operating system), a portable computer (such as anApple laptop, a laptop having a Microsoft operating system, etc.), anelectronic content reader, (such as the Amazon Kindle, the Apple iPad,etc.) and so on.

In accordance with various embodiments, receiver 108 can include areceiver transducer 109 that can be one or more of a piezoelectricallyactuated flexural mode transducer, a flextensional transducer, aflexural mode piezoelectric transducer, and/or a Bimorph-typepiezoelectric transducer (“PZT”) such as flexing type piezoelectricelement of the kind manufactured by Morgan Electro Ceramics. These canbe attached to a metal membrane and the structure can resonate in aflexing mode rather than in a brick mode. In embodiments, the structurecan be clamped around the rim by an attachment to the transducerhousing. The PZT slab can be electrically matched to the rectifierelectronics. This can be a high Q resonator (it can resonate at a singlefrequency) that can be held by very low impedance material.

Receiver 108 can further include a receiver controller 111 incommunication with the receiver transducer 109. Receiver controller 109can cause the receiver transducer 109 to receive ultrasonic waves basedon the proximity of the receiver transducer 109 to a sender transducer106. Receiver transducer 109 can convert ultrasonic energy received froma sender transducer 106 to electrical energy. Proximity can be theactual or effective distance between the receiver transducer 109 andsender transducer 106. Effective distance can be based on the efficiencyof energy transmission between receiver transducer 109 and sendertransducer 106 based on various factors that can include, withoutlimitation, their relative locations; the characteristics of theconductive medium (e.g., the air, tissue, etc.) between transmitter andreceiver; the relative orientation of the transmitter and receiver;obstructions that may exist between the transmitter and receiver;relative movement between transmitter and receiver; etc. In some cases,a first transmitter/receiver pair may have a higher proximity than asecond transmitter/receiver pair, even though the first pair isseparated by a greater distance than the second pair.

Receiver controller 109 may cause a beam of ultrasonic energy to bereceived from sender transducer 106. Further, receiver controller 109can cause the sender transducer 106 to receive ultrasonic waves havingat least one frequency and at least one amplitude.

Receiver 108 can further include a communication device (not shown) thatcan send an interrogation signal through antenna 113 to detecttransmitter 101 and help to determine characteristics of transmitter101, including sending transducer 106. The receiver communication devicecan send a control signal to a sender communication device, which can bein communication with sender controller 105. Sender controller 105 cancontrol sender transducer 106. The control signal may include thefrequency and/or amplitude of the ultrasonic waves received by receivertransducer 109. The control signal may be used to determine theproximity and/or relative orientation of receiver transducer 109 tosender transducer 106. Additionally, the control signal may include,without limitation, an instruction to be executed by sender controller105; the impedance of receiver transducer 109; a desired power level; adesired frequency, etc.

The receiver communications device may receive a control signal from asender communications device that can be in communication with sendercontroller 105. The control signal may include the frequency and/oramplitude of ultrasonic energy emitted by sender transducer 106.Additionally, the control signal may include an instruction to beexecuted by receiver controller 111 and may also include aninterrogation signal to detect a power status from receiver transducer109. The control signal may be used to determine the proximity and/orrelative orientation of receiver transducer 109 to sender transducer106.

A communications device can send a signal by modulating the ultrasonicwaves generated by the transducer for in-band communications. Thecommunication device can also be used to modulate an out-of-band signal,such as a radio signal, for communication to another communicationdevice. The radio signal can be generated by a separate radiotransmitter that may use an antenna.

The system may include communication between receiver and transmitterto, for example, adjust frequency to optimize performance in terms ofelectro acoustical conversion, modulate ultrasonic power output to matchpower demand at a device coupled to the receiver, etc. For example, ifit is determined that the ultrasound waves received by the receiver 108are too weak, a signal can be sent through the communications devices tothe transmitter 101 to increase output power. Sender controller 105 canthen cause sending transducer 106 to increase the power of theultrasonic waves being generated. In the same way, the frequency,duration, and directional characteristics (such as the degree of focus)of the ultrasonic waves may be adjusted accordingly.

Thus, in accordance with embodiments of the disclosed subject matter,the transmitter 101 and receiver 108 can communicate to coordinate thetransmission and receipt of ultrasonic energy. Communications betweenthe transmitter 101 and receiver 108 can occur in-band (e.g., using theultrasonic waves that are used to convey power from the transmitter tothe receiver to also carry communications signals) and/or out-of-band(e.g., using separate ultrasonic waves from those used to carry poweror, for example, radio waves based on a transmitter or transceiver atthe transmitter and receiver.) In an embodiment, a range detectionsystem (not shown) can be included at the transmitter 101, at thereceiver 108 or both. The range detection system at the transmitter canuse echolocation based on the ultrasound waves sent to the receiver, theBluetooth wireless communications protocol or any other wirelesscommunications technology suitable for determining the range between adevice and one or more other devices. For example, the strength of aBluetooth or Wi-Fi signal can be used to estimate actual or effectiverange between devices. For example, the weaker the signal, the moreactual or effective distance can be determined to exist between the twodevices. Likewise, the failure of a device to establish a communicationslink with another device (e.g., using a Bluetooth or Wi-Fi (e.g.,802.11) signal with another device can establish that the other deviceis beyond a certain distance or range of distances from a first device.Also, a fraction of the waves can reflect back to the transmitter fromthe receiver. The delay between transmission and receipt of the echo canhelp the transmitter to determine the distance to the receiver. Thereceiver can likewise have a similar echolocation system that uses soundwaves to assess the distance between the receiver and the transmitter.

In an embodiment of the presently disclosed subject matter, impedance ofthe first 106 and second 109 transducers may be the same and/or may besynchronized. In this regard, for example, both transducers 106 and 109may operate at the same frequency range and intensity range, and havethe same sensitivity factor and beam width.

Communications between transmitter 101 and receiver 108 can also be usedto exchange impedance information to help match the impedance of thesystem. Impedance information can include any information that isrelevant to determining and/or matching the impedance of the transmitterand/or receiver, which can be useful in optimizing the efficiency ofenergy transfer. For example, a receiver 108 can send impedanceinformation via a communication signal (e.g., a “control signal”) thatincludes a frequency or a range of frequencies that the receiver 108 isadapted to receive. The frequency or range of frequencies may be theoptimal frequencies for reception. Impedance information can alsoinclude amplitude data from the receiver 108, e.g., the optimalamplitude or amplitudes at which a receiver 108 can receive ultrasoundwaves. In an embodiment, an amplitude is associated with a frequency toidentify to the transmitter 101 the optimal amplitude for receivingultrasound at the receiver 108 at the specified frequency. In anembodiment, impedance information can include a set of frequencies andassociated amplitudes at which the receiver 108 optimally can receivethe ultrasound waves and/or at which the transmitter 101 can optimallytransmit the ultrasound. Impedance information can also includeinformation about the sensitivity of the transmitter 101 and/or receiver108, beam width, intensity, etc. The sensitivity may be tuned in someembodiments by changing the bias voltage, at least for embodiments usingCMUT technology.

Communications can also include signals for determining locationinformation for the transmitter 101 and/or the receiver 108. Inaccordance with embodiments of the disclosed subject matter, locationinformation for receivers 108 can be associated with receiveridentifiers (e.g., Electronic Identification Numbers, phone numbers,Internet Protocol, Ethernet or other network addresses, deviceidentifiers, etc.) This can be used to establish a profile of thedevices at or near a given location at one time or over one or more timeranges. This information can be provided to third parties. For example,embodiments of the system may determine a set of device identifiers thatare proximate to a given location and to each other. The fact that theyare proximate; the location at which they are proximate; informationabout each device (e.g., a device's position relative to one or otherdevice, a device's absolute location, power information about a device,etc.) can be shared with a third party, such as an third partyapplication that would find such information useful. Further, similarsuch information can be imported into embodiments of the presentinvention from third party sources and applications.

Embodiments of communications protocols between transmitter 101 andreceivers 108 can be used to dynamically tune the beam characteristicsand/or device characteristics to enable and/or to optimize thetransmission of power from transmitter 101 to receiver 108. For example,at a given distance, it may be optimal to operate at a given frequencyand intensity. A transmitter 101 may server several different devicesby, for example, steering and tuning the beam for each receiver device108, e.g., in a round-robin or random fashion. Thus, the beam for adevice A may be at 40 kHz and 145 dB, device B may be at 60 kHz and 130dB and device C at 75 kHz and 150 dB. The transmitter can tune itself totransmit an optimally shaped beam to each of these dynamically, changingbeam characteristics as the transmitter shifts from one device toanother. Further, dwell time on each receiver device 108 can bemodulated to achieve particular power transfer objectives.

In an embodiment, a transmitter 101 can receive a signal (one or morecontrol signals) from a receiver 108 indicating one or more of thereceiver's distance, orientation, optimal frequencies, amplitudes,sensitivity, beam width, etc. For example, optimal frequency when areceiver is less than 1 foot away from a transmitter may be 110 kHz witha 1.7 dB/ft attenuation rate, and optimal frequency when a receiver isfarther than 1 foot away from a transmitter may be 50 kHz with a 0.4dB/foot attenuation rate. The receiver can detect the distance andprovide a signal to the transmitter to change its frequency accordingly.In response, the transmitter can tune itself to transmit the best beampossible to transfer the most power in the most reliable fashion to thereceiver. These parameters can be dynamically adjusted during thetransmission of ultrasonic energy from the transmitter to the receiver,e.g., to account for changes in the relative positions of thetransmitter and receiver, changes in the transmission medium, etc.

Likewise, a receiver 108 may configure itself in response to signalsreceived from a transmitter 101. For example, a receiver 108 may tune toa given frequency and adjust its sensitivity to most efficiently receiveand convert ultrasound waves from the transmitter 101 to electricalenergy.

Dwell time of a transmitter 101 on a receiver 108 can also be adjustedto optimize the energy delivered by a transmitter to several receiversaround the same time. For example, the transmitter 101 may receive powerrequirements information from each of five receivers. It may dwell onthe neediest receiver for a longer time interval than a less needyreceiver as it services (e.g., sends ultrasound waves to) each receiver,e.g., in round-robin fashion.

Embodiments of the present invention include a system that can include asender transducer coupled to the amplifier. The sender transducer can bea capacitive micromachined ultrasound transducer, another type ofcapacitive ultrasound transducer, an electrostatic ultrasoundtransducer, a piezoelectric type ultrasound transducer, etc. Acapacitive transducer includes any transducer that converts anycapacitively-stored energy into ultrasonic energy. An electrostatictransducer is one that uses any electrostatically-stored energy intoultrasound energy. A piezoelectric-type transducer is one that generatesultrasonic energy based on subjecting dielectric crystals to mechanicalstress.

The transducer can be configured as an array of transducers and/orapertures. This can be used to produce a beam of ultrasonic energy. Thetransducer can be controlled by the sender controller to produce one ormore ultrasonic beams and can produce each such beam or combination ofbeams with a given shape, direction, focal length and any other focalproperty of the beam. The transducer can include one or more steeringcomponents, including one or more electronic steering components, e.g.,one or more configurations or patterns or array elements and/orapertures. One or more of the apertures can be convex to help controlbeam properties such as focal length. A transducer can have a mechanicalsteering component that works alone or in combination with one or moreelectronic steering components to control focal properties of one ormore ultrasonic beams.

In accordance with embodiments of the present invention, a system caninclude a sender that has a first value of a configuration parameter. Aconfiguration parameter can be used to describe an actual or potentialstate or condition of a sender or a receiver and can include, forexample, an amplitude, a frequency, a steering parameter, aninstruction, a power status, a transmitter characteristic and a receivercharacteristic. A sender characteristic can describe an actual orpotential condition of the sender or receiver. For example, a sendercharacteristic can relate to the power state of the sending transducerand have the values ON (emitting ultrasound to be converted intoelectrical energy by a receiver) or OFF. Another power configurationparameter can relate to the power level of the emitted ultrasonic energyin various units, such as watts per square inch, decibels, etc.

A characteristic can describe an actual or potential condition of thesender or receiver that can be fixed. For example, a characteristic canbe a telephone number, Electronic Serial Number (ESN), Mobile EquipmentIdentifier (MEID), IP address, MAC address, etc., or a mobile orstationary device that can be a sender or receiver. A characteristic canbe a fixed impedance or other electronic property (e.g., transducertype, software/firmware version, etc.) of a device.

In accordance with embodiments of the present invention, a device has afirst configuration parameter. Based on input received through thesender communications device, the sender can change its configurationparameter value to a second configuration parameter value and therebychange its state and/or behavior. Mechanisms for changing the senderconfiguration parameter can include receiving a new configurationparameter value through the communications device. The new configurationparameter value can originate from a receiver to which the sender is orintends to transmit ultrasonic energy. For example, a sender can betransmitting ultrasonic energy at a first power level and a receiver cansend a message to the sender requesting that the energy be transmittedat a second power level. For example, a receiver can send a requestasking that the power of transmitted ultrasound be boosted from 120 dBto 140 dB. The sender can then change its power level configurationparameter from 120 dB to 140 dB.

Another mechanism is to change a first configuration parameter based oninput received through the communications device, even when that inputdoes not specify a new (second) value for the configuration parameter.For example, input can be received at the sender communications devicefrom a receiver that includes a request to increase the power of thetransmitted ultrasonic energy. In response, the sender can change thevalue of the power configuration parameter from the first value to asecond value, e.g., from 120 dB to 140 dB. Likewise, one or moreconfiguration parameters can be changed based on a combinations ofinputs from one or more receivers or third parties. For example, a beamshape can be changed based upon a receiver characteristic, such as thetype of receiver transducer at the receiver.

A configuration parameter can be or include one or more steeringparameters. Examples of steering parameters include a steering angle,such as the angle at which a mechanical tilt device has disposed or candisposed one or more elements of a transducer; a dispersion angle, suchas the angle at which a threshold power occurs in an ultrasonic beam(e.g., the beam width expressed as an angle); a focal length, such as adistance in centimeters at which an ultrasonic beam becomes mostfocused; a transmitter location, such as the angle and distance of areceiver from a transmitter, or the distance of a transmitter from areceiver, or the absolute position (e.g., from a given reference point)of a sender or receiver; and a relative orientation of a sender andreceiver, such as the difference in the relative orientation of a sendertransducer and a receiver transducer, expressed in the degrees fromparallel. For example, when one transducer is parallel to another, theycan be said to have a zero degree offset. When one is perpendicular inorientation to another, they can have a ninety degree offset, etc.

Another mechanism is to change a first steering parameter in order toadjust and/or improve the efficiency of the transmission of ultrasonicenergy to a receiver. The steering parameter can be changed based oninput received through the communications device, even when that inputdoes not specify a new (second) value for the steering parameter. Forexample, input can be received at the sender communications device froma receiver that includes an amount of the transmitted ultrasonic energybeing received, e.g., 120 dB. In response, the sender can change thevalue of the steering parameter, e.g., relative orientation, from thefirst value to a second value, e.g., from a ninety degree offset to azero degree offset. As a result of changing/adjusting the steeringparameter, the efficiency of the transmission of ultrasonic energy tothe receiver may improve, and the amount of the transmitted ultrasonicenergy being received may increase, e.g., from 120 dB to 140 dB. Forexample, the amount of power at the receiver can be monitored by thereceiver and used as a basis for generating an input to be sent to thesender to adjust one or more of its configuration parameters. This canchange the way in which ultrasonic energy is transmitted by the senderto the receiver, e.g., by changing the tilt of a mechanical steeringmechanism for the sender transducer, by changing the power level of thetransmitted ultrasonic energy, by changing the electronic steering andbeam shaping of the ultrasonic energy at the sender, etc. In this way,the receiver can provide real-time or near-real-time feedback to thesender so that the sender can tune the way in which it sends ultrasonicenergy to the receiver to improve the rate at which energy istransferred (e.g., power), the continuity of energy transfer, theduration of energy transfer, etc.

Beam steering and focusing can be achieved by causing the controller tomodulate (control) the phase of the electrical signal sent to thesending transducer or to various elements of the sending transducer. Forwide-angle steering, elements of size λ/2 can be used, e.g., having asize of around 4 mm. Some semiconductor companies (Supertex, Maxim,Clare, etc.) manufacture high voltage switch chips that can allow a fewhigh-power oscillator circuits to take the place of thousands oftransmitters. An example of a useful design can have four oscillatorswith phases of 0, π/2, π and 3π/2. Switches can be arranged so that eachtransmit element can be connected to any of the four phases. The pitchof the switch-matrix can then be smaller than the pitch of thetransducer array, which can facilitate interconnection. A small amountof memory can store the entire set of switch arrangements needed for anarbitrary number of steering and focusing positions. A simplemicrocontroller (e.g., an ARM microcontroller) can manage thesteering/focusing computation.

Beam steering and focusing can be made more manageable in various ways.An electronic steering mechanism can be combined with a mechanical tiltmechanism in a direction orthogonal to that of the electronic steeringmechanism to steer and focus the beam. For example, the transmitter canbe relatively fixed in azimuth (horizontal dimension) but mechanicallysteerable in elevation (vertical dimension). Tracking vertically can beachieved by a mechanical tilt, driven by the signaling from thereceiver, or from a transmitter, either directly or through thereceiver, or with input from both and/or a third party, such as apower-tracking server. Electronic steering and focusing can be used forthe azimuthal (horizontal) beam.

Some embodiments can tilt in both azimuth and elevation. In such cases,a two dimensional array with certain elements (e.g., a 15×15 array of 2λelements) can perform focusing and steering. In some embodiments, theelement size can grow from λ/2 to 2λ or larger. In some embodiments, theelectronically steered array can be embedded in a mechanically focusedtransducer. A smaller matrix array can be positioned at the center ofcurved transducer. The curvature can create a focus in a given directionand at a certain average depth, e.g., one meter. The electronicallyfocusing portion in the center can further adjust the focusingcharacteristics of the beam.

In some embodiments, the output can be split asymmetrically betweenazimuth and elevation, allowing for sophisticated beam control. Invarious embodiments, the aperture can be divided into severalsub-apertures. Some or all of the sub-apertures can have differentsteering capabilities, enabling such an arrangement to produce aplurality of foci, which may be adjacent to each other. FIG. 2 shows adivided aperture apparatus in accordance with embodiments of the presentinvention. Source aperture 201 of can be divided into separatesub-apertures 202, 203 and 204. Each sub-aperture 202, 203 and 204 hasits own target focus 205, 206 and 207, respectively. The phase of eachof the three sources shown in FIG. 2 can be altered to change the focallength of the elevation aperture. The beam steering can be mechanical,electronic, or a combination of the two. This arrangement can also befocused by changing the phase between the sources. The efficiency of thetransmitter can be maintained for targets over a range of depths aroundthe mechanical foci established by the curvature of the sources.

FIG. 3 shows another focusing apparatus that uses azimuth aperturedivision to allow for an extended focus range over the target. Sourcetargets 301, 302, 303 and 304 have respective target foci 305, 306, 307and 308. Steering and focusing can be accomplished electronically,mechanically, or a combination thereof. In the embodiment shown in FIG.3, the element size can be made small enough to avoid the need foraperture curvature and/or mechanical tilt. Dividing the array intosegments can increase the size of the focal spots and allow them to bejuxtaposed. The foci can move around on the surface of the receiver,e.g., to optimize the overall power transfer.

A mobile device application (e.g., an iPhone or Android application) maybe associated with an embodiment of the present system to aid the user.The associated mobile application may locate an ultrasonic power system,in accordance with an embodiment of the disclosed subject matter, nearor within range of the user's location. The mobile application maypinpoint the user's exact location and compare it to the strongest powersignal location in the room, and direct the user to that power location.The mobile application may communicate with corresponding applicationson other mobile devices, e.g., to share location information,transmitter and/or receiver information, data about the transmissivityof a given medium, etc.

In accordance with embodiments of the present invention, a given devicemay act as essentially as a relay between an initial transmitter and aterminal receiver device. Such a device (a “relay device” or an“intermediate device”) may receive power from a first device, convert atleast a part of the received power to electrical energy, re-convert itto acoustic energy and then beam that acoustic energy to the terminalreceiver device. This can be useful when the terminal device may be outof range of the initial transmitter device, especially when the initialtransmitter device stores a substantial amount of energy or is connectedto a larger source of energy, such as an electrical outlet or a largeexternal battery. This can also be used to arrange for a transfer energyfrom a device that has sufficient or an excess amount of stored energyto a device in need of energy, even when the latter may be out of rangeof the former without a relay or intermediate device.

The mobile application may also inform the user of how quickly itsmobile application device is being charged and how much more powerand/or time the device requires until it's fully charged. Additionally,the mobile application can indicate the user's “burn rate” based on theamount of data being used on the device at a given time based on avariety of factors, for example, how many programs/applications are openand can indicate that the device will need to charge again in a giventime period. The mobile application may tell the user when the device isusing power from the device battery or power from the wireless powersystem. For example, the mobile application may have a hard or softswitch to signal the transmitter when the device battery is less than20% full, thereby reducing the use of dirty energy and allowing thesystem to supply the most power to those who need it to the most.Additionally, the user may have the ability to turn off their ultrasonicreceptor and/or transmitter using the mobile application.

At least part of the receiver 108 may be in the shape of a protectivecase, cover, or backing for a device, such as a cell phone, that may beinside or outside the physical device. An energy storage device, such asa rechargeable battery, may be embedded within the receiver case. Thereceiver 108 may also be used in other devices such as a laptop, tablet,or digital reader, for example in a case or backing therefor. Thereceiver 108 may be embedded within the electronic housing or can be aphysical attachment. The receiver 108 can be any shape or size and canfunction as an isolated power receiver or be connected to a number ofdevices to power them simultaneously or otherwise.

In an embodiment of the disclosed subject matter, the receiver 108 canbe a medical device such as an implant, for example a pacemaker, or drugdelivery system. The implant can be powered, or the storage device canbe charged, using an ultrasonic transmitter 101. The characteristics ofthe transmitter 101 and/or receiver 108 can be tuned taking into accountthe power needs of the device, the conduction parameters of the tissuebetween the transmitter 101 and receiver 108, and the needs of thepatient. For ultrasonic power transmission through animal or planttissue, the receiver 108 can be embedded in a medical device and/ortissue to power or charge a chemical deliver or medical device such asan implanted device. For example, a transmitter 101 could be programmedto emit ultrasound waves at a given time to a receiver 108 locatedwithin a pacemaker device implanted in the body of a patient.

Certain embodiments of the present invention can be designed to delivera relatively uniform pressure to a rectangle such as a surface of, on orin a mobile device. For example, an embodiment can be designed todeliver acoustic energy to a mobile device such as a smartphone of size115×58 mm at a distance of one meter from the transmitter with atransmit frequency in the range of 40-60 kHz (i.e. the wavelength can be5.7 to 8.5 mm.)

The maximum power in some embodiments from transmitter to receiver canbe 316 W·m⁻² , while the normalized amplitude or “gain” can becharacterized as the pressure created from 1 Pa at the surface of thetransmitter. A gain of less than one could mean that the energy transferis less than ideal. A gain above one could mean that the power densityat the transmitter should be reduced, e.g., for regulatory compliance,which may also be less than ideal. A design could create a gain of one,constant over the receiver area, and a gain less than one everywhereelse. The system can track the motion of the phone and limit power lossin the face of relative motion and/or position change of the transmitterin relation to the receiver and/or vice versa.

Phase change across the phone can be minimized, even in view of changesin the angle between the plane of the transmitter and receiver, whichcan be facilitated by using separate receiver patches on the phoneand/or with a multi-element transmitter, which can also raise theoverall efficiency through better control of the acoustic field.Steering and focusing can be achieved electronically by varying thephase of the transmitter wave across the elements. Different steeringangles and focus depths can have different values of phase at eachelement.

Various embodiments of the present invention can track the relativeposition and orientation of a transmitter and receiver, e.g., through aniOS or Android application and a wireless protocol such as Bluetooth or802.11. Closed-loop communication between transmitter and receiver canpermit the transmit beam to track the mobile device to minimize thephase changes of the beam across an element on or in the receiver.

When a receiver arrives within range of a transmitter, a two-waycommunication can be initiated. The receiver can signal its location andrequest transmission of acoustic power. As charging takes place, thephone can updates the transmitter about its location, the amount ofpower received and the distribution of acoustic energy at the receiver.An alert can be sent if the receiver is positioned in an orientation orlocation where the power transfer is inefficient. The foregoingdescription, for purpose of explanation, has been described withreference to specific embodiments. However, the illustrative discussionsabove are not intended to be exhaustive or to limit embodiments of thedisclosed subject matter to the precise forms disclosed. Manymodifications and variations are possible in view of the aboveteachings. The embodiments were chosen and described in order to explainthe principles of embodiments of the disclosed subject matter and theirpractical applications, to thereby enable others skilled in the art toutilize those embodiments as well as various embodiments with variousmodifications as may be suited to the particular use contemplated.

The invention claimed is:
 1. A system, comprising: a sender comprising:a first signal generator; a first amplifier coupled to the first signalgenerator, said first amplifier configured to receive power from a powersource and to generate an electrical transmission signal adapted to beused to generate ultrasonic waves; a sender transducer coupled to thefirst amplifier, the sender transducer adapted and configured togenerate ultrasonic waves based on the electrical transmission signalreceived from the amplifier, the sender transducer comprising at leastone transmit element; a sender controller coupled to at least one of thefirst signal generator, the first amplifier and the sender transducer;at least one switch coupled to the at least one transmit element of thesender transducer, the at least one switch adapted and configured toselect an oscillator circuit for the at least one transmit element; atleast four oscillator circuits coupled to the at least one switch, eachof the at least four oscillator circuits adapted to modulate the phaseof the electrical transmission signal; and a sender communicationsdevice adapted to communicate with a receiver communications device; andthe receiver comprising: a receiver transducer adapted and configured toreceive ultrasonic waves generated by the sender transducer, to generatea receiver electrical signal based on the received ultrasonic waves, andto connect to a receiver electrical storage device adapted andconfigured to store electrical energy based on the receiver electricalsignal generated by the receiver transducer; a receiver communicationsdevice adapted and configured to send input to the sender communicationsdevice; and a receiver controller coupled to at least one of thereceiver transducer and the receiver electrical storage device.
 2. Thesystem of claim 1, wherein the receiver further comprises: a receiverelectrical storage device adapted and configured to store electricalenergy based on the receiver electrical signal generated by the receivertransducer.
 3. A system, comprising: a signal generator; an amplifiercoupled to the signal generator, said amplifier configured to receivepower from a power source and to generate an electrical transmissionsignal adapted to be used to generate ultrasonic waves; a sendertransducer coupled to the amplifier, the sender transducer adapted andconfigured to generate ultrasonic waves based on the electricaltransmission signal received from the amplifier, the sender transducercomprising at least one transmit element; at least one switch coupled tothe at least one transmit element of the sender transducer, the at leastone switch adapted and configured to select an oscillator circuit forthe at least one transmit element; at least four oscillator circuitscoupled to the at least one switch, each of the at least four oscillatorcircuits adapted to modulate the phase of the electrical transmissionsignal; and a sender controller coupled to at least one of the signalgenerator, the amplifier and the sender transducer; and a sendercommunications device adapted to communicate with a receiver.
 4. Thesystem of claim 3, wherein the at least one switch comprises a highvoltage switch chip.
 5. The system of claim 3, wherein the at least fouroscillator circuits comprise a first oscillator circuit with a phase of0, a second oscillator circuit with a phase of π/2, a third oscillatorcircuit with a phase of π, and a fourth oscillator circuit with a phaseof 3π/2.
 6. The system of claim 3, wherein the phase of an ultrasonicwave generated by the at least one transmit element of the sendertransducer is the phase of the one of the at least four oscillatorsselected for the at least one transmit element by the at least oneswitch.
 7. The system of claim 3, wherein the at least one switch andthe at least four oscillators steer the ultrasonic waves generated bythe sender transducer.
 8. The system of claim 3, wherein the at leastone switch and the at least four oscillators focus the ultrasonic wavesgenerated by the sender transducer.
 9. The system of claim 3 comprisingadditional switch elements and additional transmit elements, wherein anyof the at least four oscillators can be selected for the at least onetransmit element and each of the additional transmit elements by one ormore of the at least one switch element and the additional switchelements.
 10. The system of claim 3, wherein an oscillator circuitselected for a transmit element by a switch element is connected to thetransmit element by the switch element.
 11. The system of claim 3,wherein the at least one switch is part of a switch matrix, the transmitelement is part of a transducer array, and wherein the pitch of theswitch matrix is equal to or smaller than the pitch of the transducerarray.
 12. A system, comprising: a signal generator; an amplifiercoupled to the signal generator, said amplifier configured to receivepower from a power source and to generate an electrical transmissionsignal adapted to be used to generate ultrasonic waves; a sendertransducer coupled to the amplifier, the sender transducer adapted andconfigured to generate ultrasonic waves based on the electricaltransmission signal received from the amplifier, the sender transducercomprising a transducer array of transmit elements; a switch-matrixcomprises switches coupled to the transmit elements of the sendertransducer, the switches adapted and configured to select, for each ofthe transmit elements, an oscillator circuit; at least four oscillatorcircuits coupled to the switches of the switch-matrix, each of the atleast four oscillator circuits adapted to modulate the phase of theelectrical transmission signal; and a sender controller coupled to atleast one of the signal generator, the amplifier and the sendertransducer; and a sender communications device adapted to communicatewith a receiver.
 13. The system of claim 12, wherein the at least fouroscillator circuits comprise a first oscillator circuit with a phase of0, a second oscillator circuit with a phase of π/2, a third oscillatorcircuit with a phase of π, and a fourth oscillator circuit with a phaseof 3π/2.
 14. The system of claim 12, wherein the switches of theswitch-matrix and the at least four oscillator circuits steer and focusthe ultrasonic waves generated by the sender transducer.
 15. The systemof claim 12, wherein the pitch of the switch matrix is equal to orsmaller than the pitch of the transducer array.
 16. A method comprising:selecting a switch arrangement associated with one or both of a steeringposition and a focusing position for a switch-matrix; and switchingswitches in the switch-matrix in accordance with the selected switcharrangement to connect at least one transmit element to one of at leastfour oscillators; modulating a phase of an electrical transmissionsignal from an amplifier with the one of the least four oscillatorscircuits; and emitting from the transmit element an ultrasonic wavegenerated from the electrical transmission signal modulated by the oneof the at least four oscillator circuits.
 17. The method of claim 15,further comprising: receiving a configuration parameter from a sender;and selecting the switch arrangement based on the configurationparameter.
 18. The method of claim 17, wherein the at least oneconfiguration parameter is a steering parameter.
 19. The method of claim17, wherein the at least four oscillator circuits comprise a firstoscillator circuit with a phase of 0, a second oscillator circuit with aphase of π/2, a third oscillator circuit with a phase of π, and a fourthoscillator circuit with a phase of 3π/2.
 20. A method comprising:selecting a switch arrangement associated with one or both of a steeringposition and a focusing position for a switch-matrix; and switchingswitches in the switch-matrix in accordance with the selected switcharrangement to connect each transmit element in a transducer array of asender transducer to one of at least four oscillators; modulating aphase of an electrical transmission signal from an amplifier with theeach of the least four oscillators circuits; and emitting from eachtransmit element an ultrasonic wave generated from the electricaltransmission signal modulated by the one of the at least four oscillatorcircuits to which the transmit element is connected by the switches inthe switch element.
 21. The method of claim 20, wherein the at leastfour oscillator circuits comprise a first oscillator circuit with aphase of 0, a second oscillator circuit with a phase of π/2, a thirdoscillator circuit with a phase of π, and a fourth oscillator circuitwith a phase of 3π/2.
 22. The method of claim 20, wherein at least oneof the transmit elements is connected by the switches to an oscillatorcircuit that is different from an oscillator circuit to which at leastone other transmit element is connected.